chromium/chrome/test/data/extensions/api_test/websocket/manifest.json

{
  "name": "websockets tests",
  "version": "0.1",
  "manifest_version": 2,
  "description": "Sanity check that WebSockets work for extensions. The majority of this is implemented (and tested) in WebKit, but we have a sanity test here just to make sure the integration with Chromium keeps working.",
  "background": {
    "scripts": ["test.js"]
  }
}